Question

The name “view model” suggests that it models the data for the view. That much is obvious. What else can or should go in the view model?

As an example, a view might display a list of items in a shopping cart, fields for customer’s credit card info, and fields for customer’s billing information. The view model might contain properties for all that OR it might only contain properties for the shopping cart items.

Answer 1

The view model is a class that represents the fields that your view shows/modifies. So for example if you are going to show a shopping cart and customer’s credit card all on the same page these properties should all belong to the view model.

You could even put properties like this in your view model if the view is going to show a drop down list of day names:

public IEnumerable<SelectListItem> DayNames
{
    get
    {
        return CultureInfo
            .CurrentCulture
            .DateTimeFormat
            .DayNames
            .Select((dayName, index) => new SelectListItem 
            { 
                Value = index.ToString(),
                Text = dayName
            });
    }
}